1. Technical Field
The technical field relates to an interchangeable lens, a camera body, and a camera system provided with the interchangeable lens and the camera body.
2. Related Art
JP-A-2006-215310 has disclosed an interchangeable lens system that is provided with a video camera, an interchangeable lens for a single-lens reflex camera that is attachable to the video camera and an exchange adapter used for connecting these. The interchangeable lens for a single-lens reflex camera is designed so as to shoot a still image. Therefore, in general, upon receipt of diaphragm-driving control from the video camera, the interchangeable lens controls the diaphragm so as to be driven at the highest speed. However, in a case where the diaphragm is always driven at the highest speed, upon shooting a moving image by the video camera, it fails to carry out a smooth diaphragm operation in response to a variation in light amount due to a change in the subject, resulting in a failure to execute a smooth AE control operation. Therefore, the interchangeable lens system of JP-A-2006-215310 places the exchange adapter between the video camera and the interchangeable lens for a single-lens reflex camera, and by using the exchange adapter, an optimal driving speed for the diaphragm of the interchangeable lens is calculated, and the diaphragm is thus controlled so that a smooth diaphragm operation is carried out, and it becomes possible to execute an AE control operation smoothly.
As described above, since the conventional interchangeable lens for a single-lens reflex camera is designed so as to shoot a still image, it is not suitable in general for use in shooting a moving image. For this reason, in a case where the interchangeable lens for a single-lens reflex camera is used for shooting a moving image, the exchange adapter needs to be attached thereto, as in the case of JP-A-2006-215310. However, in the exchange adapter of JP-A-2006-215310, a driving speed to be used upon driving the diaphragm is not set by taking into consideration an aperture value. Consequently, when the aperture value is abruptly changed upon shooting a moving image, it fails to realize a natural change in light amount, resulting in a problem of unnatural image quality. Consequently, it is not possible to realize a smooth change in brightness in an image in accordance with a diaphragm control operation, failing to obtain superior image quality upon shooting a moving image.
To solve the above-mentioned problems, an object is to provide an interchangeable lens and a camera body that are capable of providing superior image quality even when shooting a moving image, and a camera system provided with such interchangeable lens and camera body. More specifically, it achieves an interchangeable lens and a camera body that can achieve a smooth variation in brightness in an image in accordance with a diaphragm control operation, and a camera system provided with such interchangeable lens and camera body.